LAS VEGAS (KLAS) — It’s not all bad news when talking about Lake Mead, in fact, recently, the news about its rising water levels have been good. Now, we are getting a clearer picture of what is causing the lake to rise more than three feet since the beginning of August.
On Aug. 1 the lake’s water level was 1,040.99 feet above sea level. As of noon on Aug. 31, the level was 1,044.32 feet, an increase of 3.3 feet.
The Bureau of Reclamation (BOR) — which oversees water distribution and collection along the Colorado River basin – told 8 News Now the rise was due to the increase in rainfall from the monsoonal flow and decreased demand from downstream partners (states).
We now know that, according to the BOR, 64% of the lake level rise this past month has come from rain runoff and the other 36% from decreased downstream demand.
Downstream demand is the lumped total estimate for diversions/consumptive use off the river from users downstream of Hoover Dam all the way into Mexico,” BOR Public Affairs Officer Amee Andreason said. “This includes municipalities as well as irrigation districts and farms. When we say decrease, we are referring to a real-time decrease in the amount of water that is being used compared to the original water use schedules in our models.”
This recent water level rise will also change the prediction models created by the BOR showing what can be expected months and even years ahead.
“As of August 29, Lake Mead is projected to end August about 2.5 feet higher than what was estimated in the August 24-Month Study,” Andreason told 8 News Now. “To date, we have observed about 112,000 acre-ft of additional inflow compared to what was modeled (about 1.6 ft) and we have decreased Hoover Dam releases by 67,000 acre-ft compared to our original modeled estimate (about 0.9 ft). This results in additional inflows being responsible for about 64% of the total increase in Lake Mead’s elevation.”
Simply written, more water is coming into Lake Mead from rain runoff and less water is being released downstream through the Hoover Dam because Arizona and California are using less than what was predicted.
At this time the BOR cannot officially say which state is using less water than predicted or why the state(s) are using less water, that information will be released in the September 24-Month Study.
At the same time, water levels in Lake Powell to the north continue to once again fall.
Earlier in August the BOR told 8 News Now “that as of Aug. 19 there are no significant changes to operations at Glen Canyon Dam.” This is the dam holding back water in Lake Powell.
As of Aug. 29, the water level of Lake Powell was 3,532.10 feet above sea level. Lake Powell is currently down almost 168 feet from its full pool level.
After a historic drop, the water level at Lake Powell bottomed out at 3,522.24 feet, only 10 feet lower than its current level.
Approximately 500,000 additional acre-feet of water were released from the Flaming Gorge Reservoir in late May. According to the Bureau of Reclamation, this release dropped the Flaming Gorge Reservoir by nine feet and helped raise the water level in Lake Powell by almost 20 feet.
The water level rise in Lake Powell ended in early July and has since been steadily dropping, which is typical of this time of year after the snow melt from the Colorado Rockies finished its journey from the mountains to the reservoir.